E30 Zone

Evening guys. Got a techinical issue and am hoping with the zones collective experience can put forward some suggestions!

Recently got my e30 up n the road following the sale of my truck. rumbling noises from the back which to me had all the hallmarks of a wheelbearing noise. Bought 2 wheel bearings and changed the side that seemed to make the most amount of noise.

Hardly any change. The bearing was shot so im sure this was part of the noise problem. Now im not so sure if its not the diff thats causing these rumbling noises. it tends to quieten down a lot nce yur at motorways speeds.

The second issue which may be related in some way is the speedo. I have used my brothers phone which has a gps speed calculator and according to that and my speedo there is about 8-10 mph difference. I thought this was far too quick to be a 320i!!

Could it have the wrong/broken diff on?

And as a H reg 320i auto should it be a 4.1 diff?

Any help would be very well received!

Geoff

Regarding the speedo I'm pretty certain that most (all?) e30s read higher than the actual speed and due to the simple nature of how the speedo works it doesn't matter what diff is fitted (although I could be wrong there)

When I got mine it was way out too (more than 15%) it wasn't until I took some pictures of the car that I realised that one of the rear tyres was way too small 195/45/14 instead of 195/65/14 so that might be worth checking.

willnz wrote:Diff will make no difference to the speedo over reading. Having the wrong profile tyres will. All e30s I have owned have had a 5-7mph error.

regarding the noise, is it there all the time or does it change under acceleration/deacceleration/cornering?

Will check the tyres profile, i only know they are 195..

The noise is there immediately, doesnt really change much if you take bends etc...but does quieten down at motorway speeds. The reason i thought it was the wheel bearings is you get a kind of a drone out of it where the sound pitch changes from a deeper note to a lighter note.

Hard to explain over txt. Im replacing the other wheel bearing to eliminate those for sure tmorrow then i can only presume its the diff after that.

what tyres, are you sure the rumble is not tyre noise...

Morning. Jacked it up, started it up and revd it and it's definately the diff making quite a bit of noise. Also noticed it's weeping fresh oil from the offside driveshaft seal. Im thinking it's probably run low on oil?? So I guess Im after a 4.1 open diff. A guy on the zone has said he has a 4.1 LSD but for a 320 not really worth it!!